As terminals for personal voice communication and data communication are rapidly developed, piezoelectric speakers are developed in recent years. In a piezoelectric speaker, a piezoelectric material is used as an electro-acoustic transducer element. A sound output mechanism of the piezoelectric speaker is that, an application of an AC voltage to two surface of the piezoelectric element causes a generation of shape distortion of the piezoelectric element, so that a metal diaphragm is vibrated, thereby generating a sound.
However, most of conventional piezoelectric speakers are fabricated by MEMS technologies, which results in a complex fabrication process and a high cost.